Capture the camera and method of image dataThe present invention relates to according to claim 1 or 12 preamble for capturing the image data from detection zoneCamera and method.
Camera is applied to industrial application in various ways, with automatic test object attribute, such as being checked or measured pairAs.In this case, it captures the image of object and is assessed according to task by image processing method.The another kind of cameraUsing be read code.There is the object of code disposed thereon by imaging sensor capture, identify generation in these imagesCode region, is then decoded.Code reader based on camera can comfortably cope with other code words other than one-dimensional bar codeType, these type of codes are also configured as two-dimensional and provide more information as square matrix code.The autotext of print addressThe capture of the autotext of capture (OCR, optical character identification) or manuscript is essentially the reading of code.The typical case of code readerField is supermarket check out counters, automatic package identification, sorting mail, airdrome luggage processing and other logistical applications.
Common detection case is mounted on camera above conveyer belt.When object data stream relatively moves the phase on a moving beltBetween, camera captures images simultaneously introduce other processing steps according to characteristics of objects obtained.These processing steps are, for example, to makeThe suitable specific object carried out in subject machine for being conveyed is further processed, or the model by controlling in qualityIt encloses and interior certain objects are excluded from object data stream or object data stream is categorized into multiple subobject streams to change object data stream.If cameraIt is the code reader based on camera, then identifies object according to the code disposed correctly to be classified or similar processingStep.
In order to which independently of variable striation part, many industrial camera systems use the lighting device of itself(Beleuchtung).Different types of illumination is distinguished.Other than directly illuminating (also referred to as bright field illumination),It it is known that dark-ground illumination and diffusion illumination.These illuminations are usually all mounted directly in a device, are such as added as exterior lighting.
The typical field of application of dark-ground illumination is the capture to metal surface.In this case, light is flatly injected.It is equal to the principle of the angle of emergence according to incidence angle, entire light observed person or camera deflection are opened, therefore field keeps dark.Such as tiltEdge, scratch, embossing, recess and protrusion structure can interfere the optical path of light.Under these abnormal conditions, light can be towards cameraReflect or be generally only scattering.Then, these rejected regions (Fehlstelle) seem bright in camera image.
In the case where dark-ground illumination, lighting source must be arranged in together with optical device if necessary and viewing field of cameraAt specific position and angle.Under normal conditions, light source is located at circular arrangement relative to the optical axis of camera at a certain angleOn.Therefore, light source can be no longer on common electronic circuit board (Elektronikkarte).
Diffused light may in the application that must be detected to object mirror surface, polish, glossiness or metalIt is useful.Especially difficult, these surfaces are no longer flat, but be freely formed, having fold, arch or cylinderShape.
In 1 158 460 B1 of EP, during teaching, different groups of radiated element transmitting light is controlled, and correspondingControl and illumination be applied to subsequent operation, wherein one or more characteristic features of the object captured are optimal.To the greatest extentThe radiated element that pipe is circular layout can generate illumination from different directions, but cannot generate diffusion illumination or be sufficiently used for dark fieldThe illumination of the flat angle of illumination.
1 687 752 B2 of EP is disclosed provides omnidirectional lighting in scanning means, which utilizes image sensingDevice reads code.The photocon that light exit surface deflects inward light is arranged in around the dark-ground illumination for receiving optical deviceBefore separately controllable light source.The light for changing light source, until including the code in image data until that can read.Light guideCertain depth is needed, this is what there is no problem for the application in the handheld device, but is unfavorable in industrial camera's.In addition, a light guide is respectively set in each light source, total is caused to become non-when with the relatively strong illumination of many light sourcesIt is often complicated.
1 68 8861 B1 of EP uses the adapter (Aufsatz) with reflector or light guide before illuminating code reader,And light is fallen in reading area in the other end of the adapter with the straight angle (flachem Winkel).However, the adapter is bigCode reader is increased greatly.
The dark-ground illumination and bright field illumination of known combination from 8 768 159 B2 of US.Provided with internal light source and outsidePortion's light source, the internal light source are directly incident in detection zone, therefore show bright field illumination and the exterior light with light guideSource, the external light source have the inclined light guide of exit surface for dark-ground illumination.Therefore, it is related to having in terms of dark-ground illuminationOther solutions of light guide, the solution bring the shortcomings that repeatedly mentioning in terms of complexity and size.
9 569 653 B1 of US describes the dark-ground illumination in clinoplain for code reader.It is respectively provided with useIn the individual light source of diffusion illumination and by the dark-ground illumination of reflector, diffusing globe is transmitted through in order to diffuse illumination light.It reads15 ° -30 ° of front rake of code device, and should be flushed according to the rules with the surface of code to be read.However, this will lead to changeShape and still large-scale in terms of view directions structure.
Therefore, task of the invention lies in generate suitable illumination in a manner of simple and is flexible.
The task by according to claim 1 or 12 for capturing camera and the side of the image data from detection zoneMethod is achieved.Camera acquires image data from detection zone using imaging sensor.Illumination list at least one light sourceMember illuminates detection zone thus.Foreboard is in front side, i.e., in the view directions of camera, camera or its shell is closed, thus especiallyProtect lighting unit in ground.
The present invention is based on such basic thought, i.e. light source is not directly incident in detection zone, but its light is priorIt is incident on lateral deflecting element associated with light source.Here, laterally referring in the plane perpendicular to view directionsOffset, the optical axis which transfers the reception optical device for example arranged by imaging sensor or in front of imaging sensor are trueIt is fixed.By light source generate light on deflecting element by not directionally diffusing reflection with for diffuse illumination, or reflect with being directed withFor dark-ground illumination.Therefore, deflecting element is according to illumination to be generated with irreflexive or mirror-reflection (spiegelnd)Surface.Deflecting element and light source are located at below foreboard, i.e., protect in camera and by foreboard.In this case, deflecting elementAt least part can also be constituted together with foreboard, the foreboard then integrate protection and deflection.
It is an advantage of the current invention that modular dark-ground illumination or diffusion illumination are integrated into camera.Make camera as a result,It is more easily adapted to conform to lighting condition actually required.The structure of camera is able to achieve compact and especially flat size.
Preferably, the radiation direction of light source is aligned with the view directions transverse to camera.For this purpose, it is preferred that transverse direction can be usedThe LED of radiation.As already mentioned, the view directions of camera can by imaging sensor or receive optical device optical axis comeIt limits.Lateral deflecting element is arranged in radiation direction, so that the illumination of the transmitting of light source occurs there.Transverse to visual angleThe radiation direction in direction refers to the angle of at least 70 °, at least 80 ° and preferably from about 90 °.It is also contemplated that slightly larger angle, soThe light with slight backward component of original transmission is directed in detection zone by post deflection element.Transverse to the spoke of view directionsIt penetrates direction and refers to that illumination does not need constructional depths more more than deflecting element itself in the ideal case, because deflection is actually sent outLife is in one plane.Therefore, the extremely flat structure type of lighting unit is possible.
Preferably, the radiation direction of light source is arranged outward.In this case, radiation direction have at least one relative toThe radially outer component of view directions.It is not meant as outward directly between light source and the optical centre of reception optical deviceOn the extended line of connection, when being arranged to form rectangle for example, working as multiple light sources, and being outwardly directed relative to their edge.Big area is generated by the outside radiation direction of the deflection then occurred, the area is particularly greater than by multiple light sources structure itselfAt, light is therefrom by the area of effective eradiation.This is realized again bigger apart from upper flat light angle, therefore is passed throughThe outside orientation of light source makes better use of existing size.
Preferably, deflecting element is in the edge arranged beneath of foreboard in outside.Therefore, deflection first occurs at outermost edgePlace, thus it is maximum with the spacing of reception optical device.This even can most preferably utilize existing area, because of actually front of cameraEdge become effective light source.
Preferably, deflecting element is configured to frame.Preferably, the frame surround multiple light sources, these light sources respectively toFrame alignment.This frame can be easily integrated into flat device structure, and it is flat to constitute the deflection of the light in cameraFace.
Preferably, foreboard and frame are rectangles.Frame directly matches with the shape of foreboard.This is easily fabricated and goes backObtain simple overall structure.
Preferably, deflecting element is then replaceable, is especially configured for replaceable frame, light and dark to shine in diffusionThe deflecting element for converting between the illumination of field and/or passing through other forms changes lighting parameter.According in respective camera or even answeringRequirement in uses suitable deflecting element.In this case, in the table on blunt, irreflexive surface and mirror-reflectionIt is converted between face, to obtain diffusion illumination or dark-ground illumination.Further, it is also possible to use the deflection member with different mirror shapesPart, to set other light angles, reading distance or other lighting parameters that can be adjusted by beam shaping and direction.It is excellentSelection of land, deflecting element are replaceable frames, more preferably rectangular shape.This is particularly easy to manufacture and replace.
Preferably, therefore deflecting element simultaneously is configured to together with foreboard be interchangeable with foreboard connection.This is furtherBecome easy the transformation of illumination.Illumination adjustments only must be removed foreboard together with deflecting element, and with different deflectionsAnother foreboard of element is replaced.
Preferably, deflecting element has the effective profile of optics, especially recessed profile or free form surface.Pass through this sideFormula, compared with the pure deflection of plane mirror, illumination targetedly adapts to required lighting condition even betterly.
Preferably, the multiple light sources of lighting unit, especially all light sources are arranged in common circuit board(Leiterkarte) on.Because deflecting element is responsible for suitable irradiating angle, this is possible.Light source itself can be put downIt is arranged side by side smoothly, themselves need not be with detection zone at right angle.Common circuit board reduce lighting unit itself and itsThe complexity of installation, to reduce manufacturing cost.
Preferably, lighting unit has the separately controllable light source of multiple groups.It is preferred that each of identical multiple groups of sizeIncluding at least one light source.It, should by targetedly being activated to multiple groups or intensity adjustment generates different light scenesLight scene can be predefined by parameter, but can also be arranged or be shown by the feedback of the assessment to image dataReligion.Preferably, each edge for being configured to the deflecting element of rectangular frame is provided with four groups.In this way, Ke YitongIt crosses and individually control is carried out from the change illumination of all four directions to multiple groups.
Preferably, lighting unit has the light source of different colours.Some structures, certain colors in especially certain backgroundsCoding can preferably be read in suitable illumination spectrum.This can also pass through mixing by adjusting the color of light sourceColor is realized.According to embodiment, the light source of different colours or the light source that color is changeable can be set, it is such as multi-colored led.
Preferably, camera has control and assessment unit, which is configured in image dataThe code content in cognizance code region and read the code region.Therefore, camera become according to various criteria for bar code and/Or the code reader based on camera of 2D code (being also used for text identification (OCR, optical character are read) when necessary).Furthermore it is preferred thatControl and assessment unit is arranged in the another aspect of no code read functions in ground, on the other hand this controls and execute cameraIn various tasks, such as Image Acquisition, illumination, actual and required focal position measurement and its display.
It can further develop in a similar way according to the method for the present invention and show similar advantage simultaneously.TheseAdvantageous feature illustratively but not exhaustively is described in the dependent claims for being subordinated to independent claims.
Detailed description of the invention
Illustratively other features and advantages of the present invention will be carried out according to embodiment and with reference to attached drawing below more detailedThin elaboration.In the accompanying drawings:
Fig. 1 shows the schematic cross sectional views of the camera with lighting device；
Fig. 2 shows the front views of camera；
Fig. 3 shows the detailed view of the arrangement for deflecting of lighting device；
Fig. 4 shows the schematic illustration of the visual field of the illumination and camera that generate due to deflection；And
Fig. 5 shows the 3-D view for the exemplary application that camera is installed to above conveyer belt.
Fig. 1 shows the schematic cross sectional views of camera 10.Reception light 12 from detection zone 14 is incident on reception opticsOn device 16, which is directed to light 12 is received on imaging sensor 18.Preferably, optical device 16 is receivedOptical element be designed to by multiple lens and other optical elements (such as, diaphragm, prism etc.) composition object lens, but thisIn for simplicity only indicated by lens.
In order to illuminate detection zone 14 during the shooting of camera 10, camera 10 includes lighting unit, which existsIt is shown in Fig. 1 in the form of two light sources (for example, LED or laser diode) 20.Light source 20 can be with unshowned transmitting lightIt is associated to learn device.
Light source 20 is not radiated directly in detection zone 14.On the contrary, their transmitting light 22a is first with lateral deflection firstPart 24 is aligned.According to the application of camera 10, deflecting element 24 has the surface of mirror-reflection or a surface of diffusion, and the surface is from hairIt penetrates light 22a and generates the dark-ground illumination 22b or diffusion illumination 22b entered in detection zone 14 with flat incidence angle.Then, with reference to Fig. 2Deflecting element 24 is explained in more detail to Fig. 4 and emits the optical path of light 22a-22b.
Control and assessment unit 26 is connected with lighting unit and imaging sensor, and be responsible for camera 10 in control, commentEstimate and other coordination of tasks.Therefore, which reads the image data of imaging sensor 18, so as to these figuresProcessing is carried out as data and is exported at interface 28.It is also contemplated that individually being assessed image data, especially to figureAs the code region in data is decoded, camera 10 becomes the code reader based on camera as a result,.
Camera 10 is protected by shell 30, which is receiving that light 12 is fallen into and emitting the front area of light 22b outIn closed by foreboard 32.
Fig. 2 shows the embodiment of camera 10 with front view.Before camera 10 and its foreboard 32 is rectangle, whereinThe angle of rounding indicates that the shape should not be understood with the mathematical meaning of narrow sense.The multiple light sources 20 of lighting unit are arranged in squareOn the edge of shape, but according to embodiment, can more or less it be offset inward.Preferably, light source 20 is placed in common circuit boardOn 34.
Deflecting element 24 is configured to same substantially rectangular cross-sectional configuration, ambient light source 20 reflection frames, the reflection framesThe outer edge before camera 10 is preferably comprised, so that existing surface is fully utilized as far as possible.Light source 20 is by their transmitting light22a emits outward towards the direction of deflecting element 24 or reflection frames.There, according to the embodiment of deflecting element 24, transmittingLight 22a diffusely or direct projection be deflected by detection zone 14.In the front view of Fig. 2, corresponding diffusion illumination 22b or darkField illumination 22b is come out from paper plane into detection zone 14 with flat incidence angle.It is and straight in the case where diffusion illuminates 22bThe dark-ground illumination 22b penetrated is compared, and direction can of course be specified only for central part.
Preferably, light source 20 can be controlled separately, to realize variable illumination region.In order to reduce circuit complexity, only20 groups of co- controlling light source may be sufficient.Modification to this is to distinguish the light source 20 being arranged at the respective edges of rectangleCombination is in groups.It is then possible to the illumination 22b from certain directions targetedly be generated, especially in control and assessment unitIt is generated in 26 in conjunction with the image procossing of the image data of imaging sensor 18, to be looked in this way for corresponding applicationIt is arranged to most possible illumination.
In another preferred embodiment, using the light source of polychrome 20.These types of color can be correspondingIt is generated in light source 20, such as in the LED of polychrome, or the light source 20 adjacent to each other for using different colours, these light sources are by selectivityGround activation is used for certain colors.By illuminating the colour switching of 22b, some structures can be preferably identified, such as according to printingColor and background preferably reads the code of red light or blue light.In this case, the deflecting element 24 of mirror-reflection is notGenerate color difference.
Fig. 3 shows in cross section transmitting light 22a and illuminates the detailed construction of optical path of the 22b on deflecting element 24.?This, light source 20 is the LED with lateral light output, therefore perpendicular to the view directions of camera 10.Preferably, radiation direction is at leastTransverse to view directions, i.e., it is also contemplated that with orthogonally oriented angular range slightly devious, such as 70 ° -110 °.For example, thisIt can be deflected by the light at light source 20 rather than be realized by the LED of lateral radiation.
It is configured to that there is the deflecting element 24 on the surface of mirror-reflection to make to emit light 22a in detection zone 14 in Fig. 3Side upward deflect.In this case, the incidence angle in detection zone 14 may be due to the corresponding design of deflecting element 24And it is more flat or more precipitous than shown in, this depends on needing dark-ground illumination 22b is in which kind of spacing and form.
The profile of deflecting element 24 is constructed such that transmitting light 22a as much as possible is deflected by detection zone 14.In the example shown, recessed profile, that is, the profile assembled are selected.It can be set by the curvature and effective inclination angle of profileThe parameter of dark-ground illumination 22b, such as workplace away from, incidence angle, the size of detection zone 14 and geometry or intensity distribution.ForThis, profile also can be structured as free shape.
This optical effect can be replaced by optical module additional but unshowned between light source 20 and deflecting element 24To realize, these optical modules can for example make transmitting light 22a exist for the contoured of deflecting element 24 or together effectIt focuses on the vertical direction of Fig. 3 and thereby is incident on deflecting element 24 with assembling.In addition, optics function has can be set in foreboard 32Energy structure, such as embossing lens, prism or diffraction structure, this structure ensures that the additional variation of the incidence angle in detection zone 14Or further aggregation.
It is alternatively possible to substitute the surface with mirror-reflection by this deflecting element on the surface with diffusing scatteringDeflecting element 24.Then, the not instead of dark-ground illumination 22b of appearance, diffusion illumination 22b.
Camera 10 supports dark-ground illumination 22b and diffusion to illuminate the transformation between 22b and/or adjust by very simple rebuildWhole lighting parameter, wherein deflecting element 24 is suitble to the deflecting element 24 of new demand to replace.For this purpose, deflecting element 24 is only detachableGround is fixed in camera 10.In the case where deflecting element 24 is configured to frame, as shown in Fig. 2, the deflecting element is placed inReplaceable frame between foreboard 32 and remaining shell 30.In particularly preferred embodiments, deflecting element 24 or replaceableFrame is fixed on foreboard 32 and therefore constitutes common component.Then, deflection member is realized simply by replacement foreboard 32The replacement of part 24 and thereby realize the transformation between dark-ground illumination 22b and diffusion illumination 22b or to the adjustment of lighting parameter.
Fig. 4 again illustrates the cross-sectional view of the front area of camera 10, to illustrate detection zone 14 and herein using darkThe region that field illumination 22b illuminates.Although being equipped with light source 20 in the planes, lateral incidence angle is realized.Circuit board 34Shown part between gap be that but can be the phase with for receiving the central opening of light 12 as caused by cross-sectional viewWith circuit board 34, as Fig. 2 front view in it is visible.
Fig. 5 shows the possible application that camera 10 is mounted on 36 top of conveyer belt, and as shown in arrow 40, which willThe conveying of object 38 passes through the detection zone 14 of camera 10.Object 38 can carry code region 42 on its outer surface.Camera 10Task be, capture the characteristic of object 38, and use preferably and identify code region 42 as code reader on the way, readingIt disposes code there and is decoded, and the code is distributed into each associated object 38.In order to also identifyThe code region 44 of side placement, preferably uses additional unshowned camera 10 from different angles.